Smelling nail polish when there’s no obvious source usually means one of three things: your body is producing acetone (the same chemical in nail polish remover), your sense of smell is misfiring, or there’s an environmental source you haven’t identified. The most common medical explanation is excess ketones in your blood, which your body releases through your breath and skin, creating that distinctive sweet, chemical scent.
Acetone on Your Breath From Ketones
The sharp, fruity smell of nail polish remover is actually acetone, and your body produces it naturally when it burns fat for fuel instead of sugar. When carbohydrates aren’t available or your cells can’t use glucose properly, your liver breaks down fat and releases acids called ketones into your bloodstream. One of those ketones is acetone, and it escapes through your lungs every time you exhale.
Two common situations cause this. The first is dietary: if you’re following a ketogenic (high-fat, very low-carb) diet or fasting, your body shifts to burning fat as its primary fuel source. This creates a major spike in ketones, and the acetone smell on your breath can be strong enough that you or the people around you notice it. This is generally harmless and fades as your body adjusts, though it can persist for weeks.
The second situation is more serious. In people with diabetes, especially type 1, a dangerous condition called diabetic ketoacidosis (DKA) can develop when the body doesn’t have enough insulin. Without insulin, cells can’t absorb glucose, so the body floods the bloodstream with fat-burning hormones. Ketone levels climb to dangerous, acidic levels. Fruity or nail-polish-scented breath is one of the hallmark warning signs, alongside extreme thirst, frequent urination, nausea, belly pain, confusion, and shortness of breath. The CDC recommends calling 911 or going to the emergency room if your blood sugar stays at 300 mg/dL or above, your breath smells fruity, you’re vomiting and can’t keep food down, or you’re having trouble breathing.
Phantom Smells With No Source
If you’re smelling nail polish but nobody around you can detect it, you may be experiencing phantosmia, which is the perception of a smell that isn’t actually there. People with phantosmia commonly report chemical-type odors. These olfactory hallucinations have several possible triggers.
Migraines are one of the most common. Some people smell chemicals, smoke, or other strong odors as part of their migraine aura, the warning phase that precedes head pain. The smell can appear minutes to hours before the headache starts, or sometimes without a headache at all. Exposure to toxic chemicals like mercury or lead can also damage smell-processing pathways and produce phantom odors that linger long after the exposure.
Less commonly, phantom chemical smells can be linked to focal seizures in the brain’s temporal lobe. About 15% of people with temporal lobe epilepsy report olfactory auras, brief episodes where they suddenly smell something that isn’t present. These episodes are typically short (seconds to a couple of minutes) and may be accompanied by a strange feeling of déjà vu, a rising sensation in the stomach, or brief confusion. If you’re experiencing sudden, unexplained chemical smells alongside any of those symptoms, it’s worth getting evaluated. Diagnosis usually involves imaging studies or other neurological workup to rule out structural causes like masses or lesions.
Distorted Smell After a Virus
If your sense of smell changed after a cold, flu, or COVID-19 infection, you may be dealing with parosmia rather than phantosmia. The difference: parosmia distorts real smells rather than creating them from nothing. Your morning coffee might suddenly smell like chemicals, or a familiar shampoo could register as nail polish remover.
The leading explanation is a miswiring problem. Viruses can damage the nerve cells in the lining of your nose that detect odors. As those neurons regrow, they don’t always reconnect to the correct targets in the brain. The result is that ordinary, inoffensive smells get routed through the wrong pathways and interpreted as something unpleasant or chemical-like. Research on post-viral parosmia has found that certain highly volatile compounds with low odor thresholds (meaning your nose detects them even in tiny amounts) tend to be the ones that trigger distorted perception. Your brain picks up fragments of a complex scent rather than the whole picture, and those fragments happen to register as harsh or chemical.
Post-viral parosmia often improves over time as olfactory neurons continue to regenerate, but recovery can take months to over a year. Smell training, which involves deliberately sniffing a set of distinct scents for several minutes each day, is the most widely recommended approach for speeding recovery.
Environmental Sources You Might Miss
Before assuming the smell is coming from your body or brain, it’s worth ruling out an actual acetone source in your environment. Acetone is used in far more products than just nail polish remover. It’s a solvent in paints, coatings, adhesives, cleaning products, and some personal care items. In an enclosed room with poor ventilation, even a small amount can produce a noticeable odor. New furniture finishes, recently applied sealants, certain plastics, and craft supplies like resin or model glue can all off-gas acetone or similar-smelling compounds.
If the smell is strongest in a particular room or near a specific object, ventilation and removing the source usually solves the problem. If you’re regularly exposed to acetone vapors in a workspace, proper ventilation matters since prolonged inhalation at high concentrations can cause headaches, dizziness, and irritation of your eyes and respiratory tract.
How to Tell What’s Causing It
A few questions can help you narrow down the source. Ask someone nearby if they smell it too. If they do, it’s likely environmental. If they don’t, you’re dealing with either a metabolic cause (acetone on your breath) or a sensory one (phantom or distorted smell).
If you have diabetes or suspect you might, check your blood sugar. A reading of 250 mg/dL or higher warrants checking for ketones in your urine and contacting your care team. If you’ve recently started a low-carb diet or a fasting regimen, the acetone breath is likely a normal byproduct of ketosis and not dangerous on its own.
If the smell appears suddenly with no dietary explanation, comes and goes in brief episodes, or is accompanied by confusion, nausea, a strange rising feeling in your gut, or visual disturbances, those patterns point toward a neurological cause worth investigating. The same is true if your sense of smell has been generally “off” since a viral illness. An ENT specialist can examine your nasal passages with an endoscope, and imaging can help rule out structural problems in the sinuses or brain.